For example, where traditional gaming machines were connected by wired communication with their controllers, users were required to play games within a distance ranging from each machine proper to its wired controller.
Today, there exist gaming machines connected wirelessly (i.e., by wireless communication) with their controllers. Also, techniques have been proposed whereby the time required to establish a communication link between a gaming machine body and its controller is shortened (e.g., see Patent Document 1).
Meanwhile, where the gaming machine body is connected to its controller via a cable, with communication performed therebetween through that cable (i.e., by wired communication), the gaming machine body can supply power to the controller via the cable as well.
However, where the gaming machine body communicates wirelessly with its controller, it is difficult for the gaming machine to supply power to the controller from the gaming machine body. Illustratively, this requires the controller to incorporate a battery serving as its own power supply.
Where the controller incorporates the battery, the battery needs to be recharged when its remaining level has dropped. One way to charge the battery in the controller is illustratively to have the gaming machine body furnished with a function to supply power to an external device so that the gaming machine body connected to its controller via a cable may supply power to the controller through the cable and get the internal battery charged thereby.
Here, one way for the gaming machine body to supply power to an external device is illustratively to utilize communication pursuant to the USB (Universal Serial Bus) standard (USB communication).
The USB supports bus-powered operation, allowing a device (USB device) (target) connected to a host to be powered by the USB device.
Thus the gaming machine body is configured as a host for USB communication, furnished with a USB communication port (USB port (terminal)) in the gaming machine body, and the controller is configured as a USB device with a USB port in the controller. This enables the gaming machine body to charge the battery of the controller.
Specifically, the USB port of the gaming machine body is connected to the USB port of the controller using a USB communication cable (USB cable) so that the gaming machine body may supply power to the controller via the USB cable in USB bus-powered operation. This allows the battery of the controller to be charged.
As described, where the gaming machine body communicating wirelessly with its controller is capable of supplying power, games can be played while the USB cable is being detached from the gaming machine body or from the controller. And the battery of the controller can be charged by connecting the gaming machine body with the controller using a USB cable illustratively while games are not being played.
Meanwhile, some gaming machine bodies capable of feeding power through the USB cable might be configured to supply power only while the machine body is turned on. This type of gaming machine body is configured to stop feeding power (i.e., incapable of supplying power) while the machine is turned off.
In this case, as long as the gaming machine body is turned off, its controller cannot be charged. It follows that, in order to charge the controller, the gaming machine body needs to be switched on even if no games are being played.    Patent Document 1: Japanese Patent Laid-Open No. 2004-336740
As described above, in order to charge the controller, it is necessary to keep the gaming machine body turned on. For this reason, even after charging of the controller has been complete, the gaming machine body remains switched on until the user turns off the machine.
As a result, power is wasted on the gaming machine body.